Pedicle screw technology has been developed quickly since its introduction in 1980s and has been widely used in surgical treatment on affections such as spinal degeneration, spondylolisthesis, spinal stenosis, vertebral fracture, malformation, metastatic tumor of bone, spinal instability and the like. At present, the pedicle screw is one of the internal fixation instruments most widely used in a spine surgery, and methods for embedding the pedicle screw mainly include: 1. a posterior medisection screw placement surgery, which is a conventional surgery manner, is extensive in clinical application presently, and widely accepted by most of the clinicists, but it has some major defects of larger surgery wound, difficult exposure of a needle inlet point at the pedicle, more bleeding, longer postoperative recovery time for the patients, multiple combination of atrophy of longissimus muscle and multifidus muscle, instability due to ligament damage, and long-dated lumbago left on partial sufferers; 2. minimally invasive spine technology, i.e., posterior channel aided minimally invasive screw placement technology, which conducts the operation of placing a spinal pedicle screw with the help of such special surgery appliances and instruments like medical images, aided channel expansion and microscopic endoscope or the like, achieves the optimal therapeutic effect with minimal injury, and has the advantages of short surgical incision, small wound, less bleeding, rapid postoperative function recovery, and reduction of incidence of postoperative pains on the waist and back as compared with the conventional method. But presently, it has not been widely applied and popularized for being applied in clinic for almost 30 years since it is invented due to the expensive supporting instruments and relatively flat learning curves, and particularly, it is only limited to be developed at the spine surgery of tertiary hospitals at home presently.
A new minimally invasive technology which has the advantages of short surgical incision, small wound, less bleeding, rapid postoperative function recovery that are similar to a minimally invasive surgery, is simple and effective, and is easy to grasp, is needed in clinic presently. The inventor redesigns a set of surgical manner and surgical instrument, and improves the posterior spinal minimally invasive technology, which is simple and convenient, easier to grasp, has smaller wound than that of the conventional minimally invasive surgery, while the exposure apparatus for posterior spinal small incision pedicle screw placement is just a part thereof.
The conventional posterior spinal minimally invasive screw placement technology generally employs a kirschner wire to puncture and position the pedicle and then incise the skin, use an expander to expand from small to big in sequence till obtaining a satisfactory size, wherein the puncture approach may deviate a gap between the multifidus muscle and the longissimus muscle and enter the multifidus muscle or the longissimus muscle to cause injury of the multifidus muscle and the longissimus muscle, and meanwhile, the expansion process thereof is to tear and draw local muscles actually, which further aggravates the muscular injury.